sirius.calc_vis

calc_vis_chunk(uvw, vis_data_shape, point_source_flux, point_source_ra_dec, pointing_ra_dec, phase_center_ra_dec, antenna1, antenna2, chan_chunk, beam_model_map, beam_models, parallactic_angle, pol, mueller_selection, check_parms=True)[source]

Simulate interferometric visibilities.

Parameters

  • uvw (float np.array, [n_time,n_baseline,3], meter) – Spatial frequency coordinates.

  • vis_data_shape (float np.array, [4]) – Dimensions of visibility data [n_time, n_baseline, n_chan, n_pol]

  • point_source_flux (float np.array, [n_point_sources,n_time, n_chan, n_pol], (singleton: n_time, n_chan), Janskys) – The flux of the point sources.

  • point_source_ra_dec (float np.array, [n_time, n_point_sources, 2], (singleton: n_time), radians) – The position of the point sources.

  • pointing_ra_dec (float np.array, [n_time, n_ant, 2], (singleton: n_time, n_ant), radians) – Pointings of antennas, if they are different from the phase center. Set to None if no pointing offsets are required.

  • phase_center_ra_dec (float np.array, [n_time, 2], (singleton: n_time), radians) – Phase center of array.

  • antenna1 (np.array of int, [n_baseline]) – The indices of the first antenna in the baseline pairs. The _calc_baseline_indx_pair function in sirius._sirius_utils._array_utils can be used to calculate these values.

  • antenna2 (np.array of int, [n_baseline]) – The indices of the second antenna in the baseline pairs. The _calc_baseline_indx_pair function in sirius._sirius_utils._array_utils can be used to calculate these values.

  • chan_chunk (float np.array, [n_chan], Hz) – Channel frequencies.

  • beam_model_map (int np.array, [n_ant]) – Each element in beam_model_map is an index into beam_models.

  • beam_models (list) – List of beam models to use. Beam models can be any combination of function parameter dictionaries or image xr.Datasets. Any Zernike polynomial coefficient xr.Datasets models must be converted to images using sirius.calc_beam.evaluate_beam_models.

  • parallactic_angle (float np.array, [n_time], radians) – Parallactic angle over time at the array center.

  • pol (int np.array) – Must be a subset of [‘RR’,’RL’,’LR’,’LL’] => [5,6,7,8] or [‘XX’,’XY’,’YX’,’YY’] => [9,10,11,12].

  • mueller_selection (int np.array) – The elements in the 4x4 beam Mueller matrix to use. The elements are numbered row wise. For example [ 0, 5, 10, 15] are the diagonal elements.

  • check_parms (bool) – Check input parameters and asign defaults.

Returns

vis – Visibility data.

Return type

complex np.array, [n_time,n_baseline,n_chan,n_pol]